Joseph e



J. E. HOLVECK.

VALVE LOADING AND UNLOADI'NG DEVICE. APPLICATION mm MIG-12. ma.

1,31 6,794. Patented pt; 23,1919.

2 sugars-sneer 1 WV/gig m [ii F86 a :31 z l a WITNESSES 1' a. $214 f wrkrt am JOSEPH E. HOLVECK, OF IITTSIBUB/GH, PENNSYLVAN i1 VALVE LOADING AND UN LOADING DEVICE.

Specification of Letters Patent.

Patented Sept. as, rare.

Application filed August 12, 1918. Serial No. 249,5M.

To all whom it may concern:

Be it'known that I, Josnrn E. Honvnox, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have made anew and useful Invention in Valve Loadlng and Unloading Devices, of which the following is a specification.

This invention relates to unloading devices and more particularly to devlces for unloading and loading a pump or other fluid translating device havin suction and discharge valves and a reciprocating plunger or piston for translating fluid from one point to a point of higher pressure through the agency of the suction valves-thereof. In

.the use of high pressure pumps suchasthose used for pumping water into hydraullc ac cumulators it is now common practice to drive the pumps, which are usually of the, multiple cylinder type although not necessarily so, by means of direct connected electric motors. These motors are usually run continuously and when the necessity for operating the pump ceases instead of stopping the motor it is customary to unload the pump by opening the suction valve thereof and holding the same open for a certain time.

In the operation of a number of hydraulic presses for shaping metal such as shell blanks a number of such presses maybe fed from one hydraulic accumulator in which the pressure for example is maintained at twenty-five hundred pounds per square inch. A hydraulic pump is used for chargin the accumulator and when the accumu ator reaches its uppermost or charged position the pump is unloaded until such time as it is, necessary to again charge the accumulator and this time will be dependent u n the manner of operating the presses. feri by the accumulator therefore I term the service intermittent service. It may be necessary to charge the accumulator at times very often and atother times not so often and since the starting torque is high and the time required long if the motor driving the pump is stopped and started whenever it is necessary to operate the pump it isfound advisable and is now common to opcratethe pump continuously during the operation of the presses and the accumulator.

An object of this invention is to provide means for automatically loading and unloading the pump in such manner that the torque on the pump crank shaft and therefore on the motor is thrown on gradually starting at zero torque and gradually increasing to maximum torque.

A further object is to provide a device for automatically unloading the pump when the demand for pressure ceases and for again loading the pump at the beginning of the compression stroke thereof.

This, as well as other objects which will readily appear to those skilled in this particular art, I attain in the device described in the specification and illustrated in the drawings accompanying the same and forming a part of this application.

In t e drawings Figure 1 is a more or less diagrammatic view partially in elevation and partially in section of a device embodying this invention and Fi 2, 3 and 4 are diagrams showin the relatlon of the loading cams of the device and the pump plungers in a multiple cylinder pump of the triplex t pe.

Since one skilled in this art will understand this invention, a complete pump has not been shown neither has the accumulator or other device into which the pump dis charges since this would only complicate the application.

In describing this invention it is assumed that 5 represents one suction chamber of a multiple cylinder pump having reciprocatin plungers connectedto a crank shaft an that 6 is the suction pipe for supplying the cylinders with water or other liquid or fluid derived from any suitable source. Inlet port? of the suction chamber is controlled by means of a suction inlet valve 8 yieldingly held to its seat by means of gravity and a spring 9. Normally, suction valve 8 rises during the suction strokes to admit water to the plunger chamber supplied thereby and will close at the end of the suction stroke and during said stroke be held closed by the pressure exerted by the plunger.

A stem 10 axially alined with suction valve 8 is reciprocable within a guide 11 and through a stuffing box 12 rovided in the lower part of the suction plpe 6. The stem is weighted as by means of weights 13 for normally holding it out of contact with the suction valve and a bell-crank lever having arms 14 and 15 is, provided for raising said stem and said suction valve to unload the plunger whenthe demand for water has ceased. Y

A shaft 16 is connected up to the accumuwhen fulilly lator or other device to be supplied with water under pressure from the pump, by means of any suitable connections either mechanical or hydraulic and by the same is caused to reciprocate in the direction of arrow A when the demand for water ceases and in the opposite direction when the demand is renewed. The lower end of arm 14 of the bell-crank lever lies between two posts 17 and 18 carried by said shaft and when the shaft is moved in the direction of arrow A the bellcrank is swung and stem 10 is raised in contact with valve 8 thereby raising said valve through the medium of a coiled spring 19 positioned between the lower end member 20 of stem 10 and the upperend member 21 of a stem '22 slidable within a guide 23 provided for that purpose. The outer end of arm 15 of said bell-crank is bifurcated and straddles stem 22.

Spring 19 isinterposed in the combined stem made up of stems 10 and 22 in order that undue strains will not be put upon stem 10 or valve 8 by the action of the bellcrank during compression strokes of the plunger. If the demand for water ceases during a compression stroke spring 19 will be compressed, by the bell-crank and the pressure will be transmitted to valve 8 by means of stem 10 so that said valve will open immediately upon the commencement of the suction stroke of the plunger; spring 19 compressed by the bell-cranknot being su cient to raise valve 8 against the compression pressure.

In order that suction valve 8 may not close to load the pump during compression strokes a continuously rotating cam member 24 is provided. This cam is feathered to shaft 25 and is moved lengthwise of said shaft by means of an actuator 26 mounted onand carried by reciprocatin shaft 16. Clearance space is left between t e actuator amend the side face of cam 24 so that the cam may at times be moved independently of the actuator. Shaft 25 by means of gears 29 and 30 is caused to rotate synchronously with the ump crank shaft since shaft 28 is connecte up to the crank shaft.

Cam member 24 is provided with a circularsurface 31 upon which the lower end of stem 22 is adapted to ride when released from its raised position by the bell-crank vdurin the compression strokes of the plunger. e timing of the cam is such that as soon as the end of the compression stroke is reached point 32 of the circular surface 31 will pass under the end of stem 22 and allow the stem to drop thus releasing suction valve 8 to become operative. Cam

member 24 is provided with an inclined face 33which becomes operative durin the operation of the cam member aftert e stem 22 inclined face 33 bearing against the side of rampaa the stem forces the cam member along shaft 25 and out of position; such movement is independent of the movement of actuator 26.

Figs. 2, 3 and 4 are diagrams illustrating the relation between the cam members 24 and the crank shaft in a three plunger pump, the position of the crank and cam in Fig. 2 having been arbitrarily chosen. These three figures may also represent different positions of the crank and cam in a single plunger pump. The shape of the cam may be modified from the shape shown so long as stem 22 is allowed to drop only during the suction strokes of the plunger, thus causing the torque to be exerted gradually from zero at the beginning of the compression stroke to maximum. The mechanism is so timed that the bell-crank will lift stem 22 so as to clear cam member 24 before the cam member is moved to a position in line with said stem.

It will be understood that this invention is applicable to various types of pumps and in fact to any having suction inlet valves and a plunger or plungers.

In accordance with the provisions of the patent statutes I have described the principle of operation of my invention, together with the device which I now consider to represent the best embodiment thereof, but I desire to have it understood that the device shown is only illustrative and that the invention can be carried out in other ways.

Having thus described my invention what I claim is- 1. In combination with a pump, mechanism actuated at variouspoints in the pump cycle to interrupt delivery of said pump and means operated by said pump for preventing the resumption of delivery at any other point in the pump cycle than the beginning of a discharge stroke.

2. In a pump, means for unloading the pump, said means being adapted to cease.

cessation of the fuct1oning of said pressure controlled means, and independently of the cyclic point of said cessation.

4. In a pump, mechanism automatically interrupting delivery by the 'pump plunger, said mechanism automatically ceasing to function at varying points in the pump cycle, and means'operatmg, when said mechanism ceases. to function during a discharge stroke of said pump, to prevent resumption'of the =ently of said pump and, means operated by said pump.

pumps delivery except at the beginning of a subsequent discharge stroke.

5. In a pump, a plunger, an intake valve adapted to open to-permit charging of 'said pump and to close to permit discharging of said pump, mechanism controlledin ependto hold said valve olifn,

w en said mechanism is released during a discharge stroke of said plun er to prevent said valve from closing untll said plunger has completed said discharge stroke.

6. In a pump, a lurality of cylinders, respective plung ers t erefor, means for unloading all of sald plungers, and mechanism automatically preventing reloading of said plungers, when said means is rendered inoperative, except at a predetermined point in the stroke of each plunger, f

7. In a multicylinder pump, afilunger for ally preventing subsequent closure of said valves when said opening means is not functioning except at a predetermined point in the stroke of the plunger loadedby each valve.

In testimony whereof I have hereunto subscribed my name this 8th dayof August, 1918. a

JOSEPH E. HOLVEOK. 

